1 + 2b - 13 = 12 - 4b - 2b for b

The answer is b=3 for your problem

Remember you can do anything to an equation as long as you do it to both sides

1+2b-13=12-4b-2b

1-13+2b=12-6b

-12+2b=12-6b

add 6b both sides

-12+6b+2b=12+6b-6b

-12+8b=12+0

-12+8b=12

add 12 both sides

12-12+8b=12+12

0+8b=24

8b=24

divide both sides by 8

(8b) / 8=24/8

(8/8) b=3

1b=3

b=3